Matango, also known as Matango, Fungus of Terror and Attack of the Mushroom People, is a 1963 Japanese tokusatsu eiga. It was directed by Ishirō Honda, written by Takeshi Kimura based on the story "The Voice in the Night" by William Hope Hodgson (an adaptation credit is given to Masami Fukushima and Shinichi Hoshi, but Kimura threw out most of their contributions), and had special effects by Eiji Tsuburaya.
The movie has developed something of a cult audience over the years; partly due to its bleakness and unusual themes, particularly when compared to other Japanese films of the same period.
When a japanese yacht is damaged in a storm, its crew and passengers (all fashionable and affluent early 60s types) make their way to a nearby island. The island is apparently deserted, though the castaways soon discover a beached research ship on the other side of the island. An examination of the ship, the insides of which are encrusted with a thick mold, soon reveals that it had an international crew which appear to be involved in radiation and fallout research. Despite this it seems that the crew survived for some time after the ship was beached, however there is no indication of their current whereabouts.
Although mushrooms are unusually plentiful on the island, the ship's captain warns the passengers not to eat them because of the danger of poisoning, and to concentrate on birds and turtle eggs. However, it is soon discovered that birds are afraid of the island and that turtle eggs are scarce. A small supply of canned food is found on the research ship, but this only buys the crew some time. Inevitably, members of the crew begin eating the mushrooms. In the meantime, they also discover that the crew of the abandoned ship hadn't vanished as completely as they'd originally thought.